Electrically-driven clock.



P. A. BENTLEY. ELEGTRIGALLY muvnu CLOCK. APPLIGATION FILED JUNE 22,1911.

Patented Nov. 5, 1912.

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P. A. BENTLEY. ELEGTRIPALLY DRIVEN CLOCK.

APPLIUATION FILED JUNE 22, 1911. 1 ,043,663. Patented Nov. 5, 1912.

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I n l l K i 1 WWW PERCIVAL ARTHUR BENTLEY, OF BURTON-UPON-TRENT,ENGLAND.

ELECTRICALLY-DRIVEN oLocK.

Specification of Letters Patent.

Application filed June 22, 1911.

Patented Nov. 5, 1912. Serial No. 634,688.

To all whom it may concern;

Be it known that I, PERCIVAL ARTHUR BENTLEY, a subject of the King ofEngland, and residing at Burton-upon-Trent, Staffordshire, in England,have invented certain new and useful Improvements in ElectricallyDrivenClocks, of which the following is a specification.

This invention relates to electrically driven clocks and has particularreference to clocks of the type in which an impulse is given to thependulum by electromagnetic apparatus such for example as a coil of wirecarried by the pendulum and cot perating with a fixed magnet or viceversa, a current being caused to flow through the coil from a batteryand set of contacts controlled by the pendulum itself. The primaryfeature of the present invention is that the contacts are so arrangedthat if the amplitude of the swing of the pendulum increases above thenormal, the current is caused to exert a retarding force on the pendulumas it commences its next swing, the amplitude of the swing being thusmaintained practically constant. This is conveniently carried out byproviding the contacts, which may be in the form of fixed rails or barscooperating with rolling or other moving contacts, with auxiliary orreversing sections so that the current, instead of helping the pendulumforward on its downward swing, tends to retard that motion in anyinstance where the previous swing has been of an amplitude above thenormal.

In the accompanying drawings which illustrate one construction of anelectrically driven clock according to this invention, Figure 1 is afront elevation showing the pendulum and contacts, Fig. 2 is a sideelevation looking from right to left in Fig. 1, parts being shown insection. Fig. 3 is a diagram showing the electrical connections on alarger scale, and Fig. 4 is a similar diagram showing the connectionssomewhat modified.

Like letters indicate like parts throughout the drawings.

With reference to Figs. 1 and 2, the pendulum A carries a coil B adaptedto encircle and swing over a permanent magnet C fixed to a back-board orsupport D. Attached to the pendulum A as by a screw E is a U-shapedmember or frame F having adjustable screws or tappers F. Between thesetappers and in their path as they are reciprocated by the swing of thependulum A is a projection or head Gr forming part of a carnage G havingcontact wheels or runners G and kept in a vertical position by means ofa pendant weight G The contact wheels G run in the spaces between twosets of relatively fixed contact rails or bars supported on a bracket H.Each set of rails as may be seen more clearly by reference to Fig. 3,consists of two front sections J, J and K, K respectively and three rearsections lettered respectively J J J K K K and when the wheels G are inposition between the rails, they make electrical connection between theparticular front and rear sections upon which they may be standmg. Thecarriage itself may be made of insulating material or the wheels orrunners G may be insulated from it, for the carriage is simply intendedas a mechanical connection to maintain the runners G at a fixed distanceapart and to cause them to move backward and forward along the two setsof rails.

The ends of the coil B are connected by light wires which may be takenup the pendulum rod to terminals L which are in connection through thependulum suspension springs L with other terminals L These terminals Lare connected, one to the two inner sections J and K of the front railsand the other to the two outer sections J and K. In Fig. 3 theseconnections are shown clearly as a diagram, the terminals being left outand the ends of the coil B represented as connected directly byconductors M, M to the outer and inner sections J, K and J, Krespectively. The central section J 3 of one set of rear rails is joinedto one pole of a battery N or other source of current and is alsoconnected to the inner and outer sections K K of the other set of rails.Similarly the central section K is joined to the other pole of thebattery N and to the two outer sections J J All these connections areshown in the diagram formingFig. 3.

When the swing of the pendulum is normal, the wheel G on the left handside of the carriage G as seen in Fig. 3 Wlll remain in contact with thecentral section J the movement of the carriage being only sufficient tocause the wheel to travel from the position shown, where it makescontact between the sections J and J, to another position on the otherside of the gap between the sections J and J where it connects thesection J with the section J. Similarly with a normal swing of thependulum, the other wheel G on the right hand side of Fig. 3 firstconnects the section K with the section K and is then moved by the swingof the pendulum so that the section K is connected to the section K.This normal movement simply causes a reversal of the current in the coilB by connecting the same pole of the battery N first to one end of thecoil and then to the other end, the arrangement being simply a form ofreversing switch. The current being thus reversed through the coil atthe proper time toward the end of the swing of the pendulum, thereaction between the magnetic field of the coil and that of the magnet Cresults in a force tending to help the motion of the pendulum due togravity. The backward and forward swing of the pendulum is trans mittedto the clock train through any suitable mechanism such for example asthe pawl P and the ratchet wheel It, but the details of this mechanismform no part of the present invention.

Suppose now that the pendulum be swinging in the direction of the arrowin Fig. 3 and that the amplitude of that swing is greater than thenormal, the carriage G, and consequently the wheels G will be movedfarther to the left than they would be in normal circumstances.Consequently the wheels G will break connection with the centralsections J 3 and K and will be carried over the gap on to the extremeleft hand sections J 2 and K connecting those sections with the frontsections J and K. But as will be seen from Fig. 3, the outer sections JJ and the central section K are connected to one pole of the batterywhile the central section J 3 and the outer sections K and K* areconnected to the other pole. There fore the result of this extrememovement to the left is to re-make the connection with the coil B as thependulum begins to swing back from left to right in such a way that thecurrent in the coil is in the same direction as when the pendulum wasmaking the first part of its stroke from right to left. In other words,the current will be in such a direction as to exert a retarding forceupon the pendulum. Similarly if the amplitude of the swing of thependulum when going from left to right should be greater than thenormal, the carriage G will be carried to the right hand and will bringthe wheels G into such a position that they connect the sections J t andK to the sections J and K, and in this case the current established inthe coil B as the pendulum begins to swing from right to left will tendto retard it and restore the amplitude of the swing to the normal. Inthis manner it will be seen that any tendency to an increase in theamplitude of the swing is checked and such amplitude is maintainedpractically constant.

The relatively fixed contact rails may be mounted on sliding pieces orotherwise on the bracket H so that their position with regard to thevertical line of the pendulum may be capable of adjustment.

It will be obvious that the connections of the coil B and the battery Nmay be reversed so far as the two sets of rail contacts are concerned,for example, the ends of the coil B might be connected through the wiresM, M to the rear rails J', J J and K K, K and the battery N connectedbetween the inner sections J and K and the outer sections J and K of thefront rails. Such a method of connection is shown diagrammatically inFig. at and its operation will be precisely similar to that describedwith reference to Fig. 3.

In the construction shown in Figs. 1 and 2, the wheels G are intended torest upon and make contact between the two sets of rails beneath them,but obviously any suit able arrangen'ient of moving and fixed contactsmay be employed. For example, the rail formed of three sections may beabove that formed of two sections and the wheel G may run between themand make conncction in that way. The diagrams forming Figs. and a may betaken to represent such a modified arrangement of rails although theyalso show diagrammatically the electrical connections for theconstruction described with reference to Figs. 1. and 2. It will beunderstood that the wheels G represent some convenient form of moving orrolling contact, but any well known form of such contact may beemployed, such for in stance as a sliding contact. It is, however,preferred to use a rolling contact in order that the arrangement shallbe free from unnecessary friction.

Any source of electrical energy may be used. to furnish current for thecoil B, and it is found in practice that suflicient current may beobtained from a battery consisting of elements of zinc and carbonembedded in the earth.

Vhat I claim as my invention and desire to secure by Letters Patentis 1. I11 an electrically driven clock, the com bination with thependulum, electromagnetic means for actuating said pendulum, a source ofcurrent and means controlled by the pendulum itself for maintaining thecurrent in the same direction during the swing of the pendulum in bothdirections when the amplitude of the swing is above the normal in eitherdirection.

2. In an electrically driven clock, the combination of a pendulum,electromagnetic means comprising a magnet and coil for actuating thependulum, a source of current,

circuits connecting such source of current with the coil, a switchcontrolling said circuits and adapted to be moved by the pendulum so asto reverse the current in the coil at each normal swing of the pendulumand auxiliary circuits also controlled by the switch whereby if theamplitude of the swing increases above the normal, the direction of thecurrent is restored to normal so that a retarding force is exerted uponthe pendulum.

3. In an electrically driven clock the combination of a pendulum,electromagnetic means comprising a magnet and a coil. for actuating thependulum, a source of current, rail or bar contacts, circuits connectingthe source of current and the coil with the rail contacts, a switchmovable by the pendulum and cooperating with the contacts so that with anormal swing the current in the coil is reversed at each swing of thependulum, and auxiliary contacts brought into opera tion when theamplitude of the swing of the pendulum exceeds the normal whereby thecurrent is allowed to flow through the coil in such a direction as toexert a retarding force upon the pendulum.

4:. In an electrically driven clock the combination of a pendulum, amagnet mounted adjacent to the path of motion of the pendulum, a coilmounted on the pendulum in proximity to the magnet, a source of current, rail or bar contacts, circuits connecting the source of currentand the coil with the rail contacts, a switch movable by the pendulumand cooperating with the contacts so that with a normal swing thecurrent in the coil is reversed at each swing of the pendulum, andauxiliary contacts brought into operation when the amplitude of theswing of the pendulum exceeds the normal, whereby the current is allowedto flow through the coil in such a direction as to exert a retardingforce upon the pendulum.

5. In an electrically driven clock, the co1n bination of a pendulum, acarriage moved by the pendulum, two contact-making wheels mounted on thecarriage and a set of contact rails cooperating with each wheel each setcomprising rails of three sections and two sections which are connectedby the wheel, a pendulum-actuated coil, a source of current, andconnections between the rails, the source of current and the coil suchthat with a swing of normal amplitude, the current in the coil isreversed for each swing of the pendulum, but if the amplitude increases,the direction of the current is restored to normal so that a retardingforce is exerted on the pendulum.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

PEROIVAL ARTHUR BENTLEY.

Witnesses:

B. E. DUNBAR KILBURN, AROHIBALD J. FRENCH.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

